Three-dimensional Printing Research Articles

Evaluation of the Mechanical Properties of Provisional 3DPrinted Resin After Repair with Different Materials: An In-Vitro Study.

To evaluate the mechanical properties of the 3D printed provisional restoration material that was repaired using different materials. The bar specimens have been manufactured using three-dimensional printing technology in accordance with the ISO 10477:2020 standards and divided into 5 groups randomly. For repair material application and replacement on the standardized silicone mold, the test specimens were ground at the center by 1x2x2 mm. No grinding was done on the control group specimens. Flowable composite, bis-acrylic composite resin, polymethyl methacrylate resin, and temporary 3D printing resin are utilized as repair materials (n=16). The specimens underwent a three-point-bending (3PB) test, with a cross-head speed of 1mm/min, in order to assess their flexural strength (FS) and flexural modulus (FM). The data received statistical analysis with one-way ANOVA and Tukey test. A Weibull analysis was performed, and the Weibull modulus of specimens was calculated. Control group specimens were showed the highest FS (142±12.6 MPa) and FM (4497±1205 MPa) values. Among the test groups, the utilization of temporary 3D printing resin as a repair material exhibited the greatest FS (67±33.3 MPa) values and showed statistical significance when compared to all other groups. Repairing 3D-printed provisional resin material weakens its mechanical properties. However, utilizing the own resin made of 3D-printed provisional resin material can be an effective choice for implementing minor modifications and additions.

Optimizing Diode Laser Performance: Effective Noise Reduction in a Three-Dimension Printing Machine

Optimizing Diode Laser Performance: Effective Noise Reduction in a Three-Dimension Printing Machine

Mechanical, optical and surface properties of 3D-printed and conventionally processed polyamide 12.

Polyamide-based materials are suitable for three-dimensional (3D) printing. The aim of the study is to examine the impact of aging on the mechanical, surface and optical properties of polyamide 12. A total of 116 specimens were examined, comprising 58 conventionally processed polyamide 12 (PA12_C) specimens and 58 3D-printed polyamide 12 (PA12_3D) specimens. The modulus of elasticity was determined before and after mechanical and thermal aging with 1,000, 3,000, 9,000, and 1,000, 3,000 and 7,000 cycles, respectively. The surface roughness (Ra), Ra change (ΔRa) and color change (ΔE) were examined before and after chemical aging (1, 12 and 36 days, with artificial saliva, coffee and red wine) using surface profilometry and color spectroscopy. The Kruskal-Wallis test, Mann-Whitney U test and Bonferroni-Holm correction were employed, with a significance level of p < 0.05. Before and after mechanical aging, the modulus of elasticity for PA12_3D showed significantly higher values (761 MPa and 747 MPa, respectively) in comparison to PA12_C (515 MPa and 455 MPa, respectively; adjusted p < 0.001). Additionally, before and after thermal aging, the modulus of elasticity for PA12_3D exhibited significantly higher values (833 MPa and 705 MPa, respectively) compared to PA12_C (516 MPa and 458 MPa, respectively; adjusted p < 0.001). The Ra of PA12_3D was higher than that of PA12_C at the baseline (0.41 μm compared to 0.31 μm, respectively), and remained higher during the aging process. The ΔRa values were small for both groups. The ΔE was significantly higher for PA12_3D compared to PA12_C after 12 days (6.2 (PA12_3D) compared to 4.8 (PA12_C), adjusted p = 0.003) and 36 days of storage in red wine (8.2 (PA12_3D) compared to 6.8 (PA12_C), adjusted p = 0.003). After 36 days of coffee storage, the observed changes were found to be statistically significant (8.6 (PA12_3D) compared to 6.7 (PA12_C), adjusted p < 0.001). The 3D-printed polyamide 12 demonstrated higher rigidity, Ra and discoloration compared to the conventionally processed polyamide 12. However, not all of the observed parameter differences were significant or clinically relevant. These differences may impact clasp retention, biofilm formation and aesthetic appearance. Nevertheless, the clinical efficacy of 3D printing may be significant.

Holographic multiplexing metasurface with twisted diffractive neural network

As the cornerstone of AI generated content, data drives human-machine interaction and is essential for developing sophisticated deep learning agents. Nevertheless, the associated data storage poses a formidable challenge from conventional energy-intensive planar storage, high maintenance cost, and the susceptibility to electromagnetic interference. In this work, we introduce the concept of metasurface disk, meta-disk, to expand the capacity limits of optical holographic storage by leveraging uncorrelated structural twist. We develop a physical twisted neural network to describe the optical behavior of the meta-disk and conduct a comprehensive lateral error analysis, where the meta-disk stores large volumes of information through internal structural multiplexing. Two-layer 640 µm x 640 µm meta-disk is sufficient to store over hundreds of high-fidelity images with SSIM of 0.8. By harnessing advanced three-dimensional (3D) printing technology, optical holographic storage is experimentally demonstrated with Pancharatnam-Berry metasurfaces. Our technology provides essential backing for the next generation of optical storage, display, encryption, and multifunctional optical analog computing.

Extrusion-Based Three-Dimensional Printing of Metronidazole Immediate Release Tablets: Impact of Processing Parameters and in Vitro Evaluation

PurposeThe current study assessed the potential of a pneumatic 3D printer in developing a taste-masked tablet in a single step. Metronidazole (MTZ) was chosen as the model drug, and Eudragit® E PO was used as a taste-masking polymer to produce taste-masked tablets.MethodsThe study focused on optimizing processing parameters, such as the nozzle's printing speed, the printhead's heating temperature, and the pressure. Oval-shaped tablets were printed with a rectilinear printing pattern of 30% and 100% infill and evaluated for in vitro drug release and taste masking. The 3D-printed tablets are also characterized using Differential Scanning Calorimetry (DSC), Fourier-transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM).ResultsThe infill density impacts the drug release profile of the tablets. F9, F10, and F11 displayed desired printability among the formulations, with F9 and F10 exhibiting over 85% drug release within 60 min in the in vitro dissolution study. The F9 formulation, with 30% infill, effectively masked the bitter taste of MTZ in the in vitro dissolution study carried out in a pH 6.8 artificial salivary medium. The observed release was below the tasting threshold concentration of the model drug.ConclusionIn summary, 3-dimensional extrusion-based printing combines the effects of hot-melt extrusion and fused deposition modeling techniques in a single-step process, demonstrating potential as an alternative to the fused-deposition model 3D printing technique and warranting further exploration.Graphical

Development and application of digital technology in craniomaxillofacial surgery

The treatment of craniomaxillofacial (CMF) defects and deformities is highly challenging due to the complex anatomical structures, significant individual variations and high demands for personalized reconstruction. In recent decades, the integration of cutting-edge technologies from fields such as computer science, mechanical engineering, and material science into medicine has greatly facilitated the transformation of CMF surgery from traditional, experience-based approaches to digitalized and intelligent methods. This review thoroughly analyzes the development and application areas of digital technology in CMF surgery including virtual surgical planning and facial prediction, three-dimensional printing, computer-assisted navigation and robotic surgery, virtual and mixed reality, as well as big data and artificial intelligence technologies. The aim is to offer comprehensive and in-depth reference information for the clinical practice in digital CMF surgery.

3D-printed scaffolds with controlled-releasing compounds for ectopic activation of dormant ovarian follicles

Throughout a woman&amp;rsquo;s reproductive life, hundreds of functioning follicles are activated for development, while thousands of dormant follicles remain in the ovaries. Dormant follicle activation in vitro is an effective clinical strategy for women with fertility needs who suffer from ovarian dysfunction. However, activating dormant follicles in vivo is still a challenge due to difficulties such as delivering stimulators to local sites. Here, we developed a compound-preloaded microporous scaffold by combining three-dimensional (3D) printing techniques with pharmacological activators to support and stimulate the activation and development of primordial follicles. The gelatin/alginate composite scaffolds exhibited exceptional mechanical properties and biological compatibility, effectively supporting the survival of ovarian granulosa cells for more than 7 days, which is essential for oocyte development. Furthermore, the ovarian tissue-scaffold complex successfully survived after transplantation under the mouse kidney capsule, demonstrating its excellent biocompatibility. After pre-mixing widely used clinical activators into the bio-ink, the scaffold had the ability to gradually release the mixture of compounds, effectively activating primordial follicles. By transplanting the ovary-scaffold complex containing activators into the mouse abdominal subcutaneous pocket, dormant follicles could be activated subcutaneously and developed into growing follicles. The number of growing follicles is approximately three times higher compared to the group without activators. In conclusion, by integrating biomaterials, activators, and 3D printing technology, we have developed 3D-printed biological scaffolds that can ectopically support primordial follicle activation and development in vivo. This novel approach could provide a promising strategy for treating ovarian insufficiency and endocrine disorders in the clinic, without the need for in situ ovarian tissue grafting.

Current State and Outlook in Medical 3D Printing and the Role of Radiology.

Medical three-dimensional (3D) printing is playing an increasingly important role in clinical practice. The use of 3D printed models in patient care offers a wide range of possibilities in terms of personalized medicine, training and education of medical professionals, and communication with patients. DICOM files from imaging modalities such as CT and MRI provide the basis for the majority of the 3D models in medicine. The image acquisition, processing, and interpretation of these lies within the responsibility of radiology, which can therefore play a key role in the application and further development of 3D printing.The purpose of this review article is to provide an overview of the principles of 3D printing in medicine and summarize its most important clinical applications. It highlights the role of radiology as central to developing and administering 3D models in everyday clinical practice.This is a narrative review article on medical 3D printing that incorporates expert opinions based on the current literature and practices from our own medical centers.While the use of 3D printing is becoming increasingly established in many medical specialties in Germany and is finding its way into everyday clinical practice, centralized "3D printing labs" are a rarity in Germany but can be found internationally. These labs are usually managed by radiology departments, as radiology is a connecting discipline that - thanks to the imaging technology used to produce data for 3D printing - can play a leading role in the application of medical 3D printing. Copying this approach should be discussed in Germany in order to efficiently use the necessary resources and promote research and development in the future. · 3D printing in medicine is a rapidly growing field.. · Image acquisition and processing provides an important basis for high-quality 3D models.. · Radiology, as the specialist discipline responsible for imaging, has a crucial role to play.. · Radiology should play a leading role in the introduction of 3D printing in everyday clinical practice. . · Streckenbach A, Schubert N, Streckenbach F et al. Current State and Outlook in Medical 3 D Printing and the Role of Radiology. Fortschr Röntgenstr 2024; DOI 10.1055/a-2436-7185.

Research on the method of digital technology assisted direct resin composite restoration for deep distal caries in mandibular second molars

Objective: To explore the digital design and fabrication technology of personalized restorative matrix for dental filling, and to explore the feasibility of direct resin restoration for deep caries lesions in distal neck of mandibular second molar. Methods: For patients with deep caries lesions in the distal neck of the mandibular second molar who visited the Department of Cariology and Endodontology of Peking University School and Hospital of Stomatology from September 2023 to April 2024, after preparing the cavity and gingival retractor, a three-dimensional intraoral scanner was used to obtain three-dimensional data of the patient's dentition. In the dental restoration computer-aided design software, the inlay function was used to generate the restored tooth morphology. The edge range of the personalized restorative matrix was drawn on the restored model by three-dimensional reverse engineering software to achieve edge sealing effect. The selected edge range data was processed with distal shelling to generate a digital model of a personalized restorative matrix with a thickness of 0.5 mm. A metal three-dimensional printer was used to fabricate the titanium alloy restorative matrix, and its application was completed in 10 clinical cases. The marginal adaptation and retention stability of the personalized restorative matrix were evaluated under a dental microscope, and forming effect evaluation was performed through immediate postoperative periapical radiographs. Results: The preliminary clinical application of the personalized restorative matrix fabricated using digital technology revealed that, in the treatment of 10 affected teeth, rubber dam isolation was successfully ensured, resulting in clinically effective direct resin composite restorations with optimal marginal adaptation and reasonable contours. Immediate postoperative periapical radiographs showed good convexity of the filling body, with no overhangs found. Both marginal adaptation and retention stability met the requirements of clinical treatment. Conclusions: The personalized restorative matrix designed in this study can solve the clinical problems of moisture separation and resin forming in the treatment of deep caries lesions in distal neck of the mandibular second molar, and can achieve stable and reliable adhesive restoration effects.

Preparation and property characterization of Zr-modified Si-O-C-based precursor ceramics through three-dimensional printing

Preparation and property characterization of Zr-modified Si-O-C-based precursor ceramics through three-dimensional printing

Research on Mechanical Properties of a 3D Concrete Printing Component-Optimized Path by Multimodal Analysis

Three-dimensional concrete printing (3DCP) technology with solid wastes has significant potential for sustainable construction. However, the hardened mechanical properties of components manufactured using 3DCP technology are affected by weak interlayer interfaces, limiting the widespread application of 3DCP technology. To address the inherent limitations of 3DCP technology, conventional improvement strategies, such as external reinforcement and the optimization of material properties, lead to increased production costs, complex fabrication, and decreased automation. This study proposes an innovative spatial path optimization method to enhance the mechanical performance of 3D-printed, cement-based components. The novel S-path design introduces additional printed layers in the weak interlayer regions of the printed samples. This design improves the spatial distribution of fiber-reinforced filaments in continuous weak zones, thus enhancing the functional efficiency of fibers. This approach improves the mechanical performance of the printed samples, achieving compressive strengths close to those of cast samples and only a 20% reduction in average flexural strength. Compared to using a conventional printing path, the average compressive strength and flexural strength are improved by 30% and 55%, respectively, when the S-path layout is employed in 3DCP. Additionally, this method significantly reduces the anisotropy in compressive and flexural strengths to 26% and 28% of samples using conventional printing paths, respectively. Therefore, the proposed method can improve the mechanical properties and stability of the material, reducing the safety risks of printed structures.

Three-Dimensional Printing Technology in Drug Design and Development: Feasibility, Challenges, and Potential Applications

Background/Objectives: The present investigation evaluates the impact of 3D-printing technology on the design of pharmaceutical drugs, considering the feasibility issues and problems concerning technological, pharmaceutical, and clinical matters. This paper aims to review how 3D printing can modify the traditional manufacturing of drugs with personalized medicine-therapy outcomes being individualized and optimized, hence improving patients’ compliance. Methods: The historical development of 3D printing from rapid prototyping to advanced pharmaceutical applications is discussed. A comparison is then made between traditional drug manufacturing approaches and the different techniques of 3D printing, including stereolithography, material extrusion, and binder jetting. Feasibility is assessed based on clinical trials and studies evaluating the efficacy, safety, bioavailability, and cost-effectiveness of 3D-printed drugs. Results: Current evidence indicates that material selection, regulatory barriers, and scalability issues are some of the major challenges to be overcome for wider acceptance. Other matters, such as ethical issues concerning patient data privacy, the misuse of 3D-printing technology, and technical complexities related to pharmaceutical 3D printing, are discussed further. Future applications also include bioprinting and in situ printing together with their implications for personalized drug delivery, which will also be discussed. Conclusions: This review stresses that intersectoral collaboration and the updating of regulatory frameworks are a must to overcome the barriers that confront 3D-printing applications in drug development. can could be an opportunity for innovative licensing and manufacturing techniques in pharmaceutical product development that can change the paradigm of personalized medicine through modern printing techniques.

Novel morphological classification of left atrial appendage using 3-dimensional printer -rock, paper and scissors-

Abstract Background The WATCHMAN device was developed as a permanent implantable device to seal off the LAA to prevent cardiogenic embolism. It has been used in Japan since September 2019 only for patients who are at the high risk of bleeding events. It is known that the LAA diameter of Asians is larger than that of non-Asians. Furthermore, the LAA of the Japanese are more complicated, compared to the Western. Whereas the four classifications from previous reports are widely used in the world, the classification differs with different physicians in the real-world practice. Purpose We aimed to identify the relationship between morphological features of LAA and clinical events such as ischemic stroke in Japanese patients. Methods All LAAC cases in our institution performed between February 2020 and December 2023 were retrospectively analyzed. The three-dimensional printing of LAA was generated from cardiovascular computed tomography imaging data. The shapes of the LAA were classified into 3 morphological types: (1) The LAA with bi lobe was defined as "Scissors" type; (2) The one with complicated peripheral branches was "Paper" type; (3) The simple one was "Rock" type. We examined the between the risk of cardioembolic stroke and the morphological features of the LAA. The left atrial appendage was classified by two cardiologists, and when they made different choices, we used the operator's choice. Results The cohort consisted of 116 patients, excluding 22 patients without CT scans. Of those, 30 (26%), 38 (33%) and 48 (41%) patients were divided into the Rock, Scissors and Paper types, respectively. All groups were identically matched for comorbidities. Table shows the patient characteristics and the results of univariate and multivariate analysis. There were 51 (44%) patients who had a history of cardioembolic stroke (18% vs. 30% vs. 53%; Rock vs. Scissors vs. Paper types, p-value = 0.05). In the multivariate analysis, the Paper type is the potential risk factor of cardioembolic stroke (p-value = 0.01). In addition, of those, 36 (31%), 32 (28%), 28 (24%) and 20 (17%) patients were divided into the Chicken wing, Cactus, Cauliflower and Windsock types, respectively. The four types were not associated with prior cardioembolic stroke events (18% vs. 25% vs. 55%; Chicken wing vs. Cactus vs. Cauliflower vs. Windsock types, p-value = 0.83). The match rate of cardiologists’ choice was 86.2% for the new classification and 44.8% for the classical classification. Conclusions The morphological features of LAA by three-dimensional printing was significantly related to cardioembolic stroke in this population. Patients with Paper type LAA were significantly more likely to have had a history of cardioembolic stroke. These results could have a relevant impact on the antithrombotic management of patients who are at the high risk of embolic and bleeding events and, moreover, LAAC could be the best option for these patients.

Three-dimensional printing for preoperative rehearsal and intraoperative navigation during laparoscopic rectal cancer surgery with left colic artery preservation

Three-dimensional printing for preoperative rehearsal and intraoperative navigation during laparoscopic rectal cancer surgery with left colic artery preservation

Use of scaffolds based on polyetheretherketone tubular implant in the treatment of a gunshot multifragmentary fracture of the proximal part of the shoulder with a bone defect: a case report

BackgroundIn connection with the war in Ukraine and the use of modern high-energy weapons by the enemy, the nature of injuries have changed. These changes require improvement of approaches to the treatment of patients with gunshot and mine-explosive bone defects.Case presentationWe present the case of treatment of a 28-year-old Ukranian man with a gunshot multifragmentary fracture of the proximal humerus with a bone defect using three-dimensional printing of a polyetheretherketone frame (scaffold) for alloplastic material. The analysis of this case expands the possibilities of using three-dimensional printing technologies of polyetheretherketone scaffolds in the treatment of significant bone defects.ConclusionModern military trauma requires individualized treatment for each patient. The use of individual polyetheretherketone scaffolds in the treatment of a gunshot multifragmentary fracture with a bone defect has a positive clinical effect.

Determining the effectiveness of using three-dimensional printing to train computer vision systems for landmine detection

The object of this study is the effectiveness of using three-dimensional printing to train computer vision models for landmine detection. The ongoing war in Ukraine has resulted in significant landmine contamination, particularly after russia’s full-scale invasion in 2022. Given the enormous amount of potentially landmine-contaminated land, fast and efficient demining techniques are required, as human probing and metal detectors are labor-intensive and slow-moving. Machine learning offers promising solutions to speed up the landmine detection process by deploying recognition models on robots and unmanned aerial vehicles. However, training such systems faces certain challenges. Firstly, the number of annotated data available for training is limited, which can hinder the model’s ability to generalize to real-world scenarios. Secondly, the use of real or even defused landmines is dangerous due to the potential for accidental detonation. This study aims to overcome the problem of limited data and the risk of using real landmines. Three-dimensional printing makes it possible to create safe and diverse training data, which is essential for model performance. The model trained on replicas, achieved 98 % and 91 % precision on printed and actual landmines, respectively. This high precision is attributed to the realism of copies and the use of advanced machine learning algorithms. This approach successfully addressed the research problem due to the safety, accessibility and diversity of copies. The models trained on copies of landmines could be used in humanitarian demining operations. These operations often employ unmanned aerial vehicles or robots to identify landmines that are thrown remotely, exposed on the surface, or partially hidden

Analysis of Energy Flow to the Interface Microstructure and Its Effect on Weld Strength in Ultrasonic Additive Manufacturing

Ultrasonic additive manufacturing (UAM) is a process used for the three-dimensional printing of metal foil stock that can produce near-net-shaped metallic parts. This work details the development of an energy-based tool to identify the relationships between input energy, energy stored in the interface microstructure, and the strength of the weld interface in UAM. The stored energy in the grain boundaries of the crystallized grains in the interface microstructure are estimated using the Read–Shockley relationship. The energy stored in the interface is found to be positively correlated with the resulting weld strength. An energy flow diagram is developed to map the flow of energy from the welder to the workpiece and quantify the key participating energies such as the energy of plastic deformation, energy stored in the interface microstructure, energy required for asperity collapse, and heat generation. A better understanding of the flow of energy in UAM can assist in optimizing the process to maximize the portion of energy input by the welder that is used for bond formation.

Blending Tradition and Innovation: Student Opinions on Modern Anatomy Education

Anatomy education has evolved significantly with the introduction of diverse instructional techniques. This review evaluates these methods, including traditional cadaver dissection, three-dimensional (3D) model printing, virtual dissection using tools like the Anatomage table, problem-based learning (PBL), and the use of wax and plastinated models. Each approach presents unique benefits and challenges. Cadaver dissection remains invaluable for providing hands-on experience and a deep understanding of anatomical structures, although it faces ethical, logistical, and financial constraints. Wax and plastinated models offer durable, precise representations of anatomical structures without the ethical concerns associated with cadavers. Additionally, 3D printing and virtual dissection have emerged as effective supplementary tools, enhancing spatial understanding and allowing repeated practice. PBL integrates anatomical knowledge with clinical reasoning, promoting critical thinking and problem-solving skills. The main aim of this study was to gather and analyze students’ opinions on various anatomy teaching methods, while a secondary objective was to review the literature on novel and traditional approaches in anatomy education. This review emphasizes the importance of incorporating a variety of teaching methods to create a dynamic and engaging anatomy curriculum, preparing students for clinical practice.

Solidification process of hollow metal droplets impacting a substrate

Recently, there has been a renewed interest in hollow droplet impact, as the internal bubble makes a difference in the spreading morphology during thermal spraying and three-dimensional printing. This paper is dedicated to the solidification process of a hollow metal droplet impacting a cold substrate. The influence of initial impact velocity and substrate temperature on the spreading process is numerically investigated by employing a phase-field method coupled with a solidification model. Solidification was shown to strongly alter droplet spreading and the flow state of the center liquid column. To describe the flow state of the center liquid column, three patterns, namely ‘no-jet’, ‘transition region’, and ‘counter-jet’ are defined. The simulation results show that the formation of the center counter-jet is inhibited by the solidification layer when Péclet number Pe<357, where Pe is the ratio of convection rate to diffusion rate. In addition, the critical Pe at which the phenomenon of counter-jet occurs gradually rises with the substrate temperature falling. Finally, a quantitative analysis of the maximum spreading diameter is proposed by establishing an energy conservation equation. The predicted diameters are in good agreement with the simulated results. It allows us to provide a general expression for the hollow droplets' maximum spreading diameter, using the impact and temperature parameters.

Application of electrospinning and 3D-printing based bilayer composite scaffold in the skull base reconstruction during transnasal surgery

Skull base defects are a common complication after transsphenoidal endoscopic surgery, and their commonly used autologous tissue repair has limited clinical outcomes. Tissue-engineered scaffolds prepared by advanced techniques of electrostatic spinning and three-dimensional (3D) printing was an effective way to solve this problem. In this study, soft tissue scaffolds consisting of centripetal nanofiber mats and 3D-printed hard tissue scaffolds consisting of porous structures were prepared, respectively. And the two layers were combined to obtain bilayer composite scaffolds. The physicochemical characterization proved that the nanofiber mat prepared by polylactide-polycaprolactone (PLCL) electrospinning had a uniform centripetal nanofiber structure, and the loaded bFGF growth factor could achieve a slow release for 14 days and exert its bioactivity to promote the proliferation of fibroblasts. The porous scaffolds prepared with polycaprolactone (PCL), and hydroxyapatite (HA) 3D printing have a 300 μm macroporous structure with good biocompatibility. In vivo experiments results demonstrated that the bilayer composite scaffold could promote soft tissue repair of the skull base membrane through the centripetal nanofiber structure and slow-release of bFGF factor. It also played the role of promoting the regeneration of the skull base bone tissue. In addition, the centripetal nanofiber structure also had a promotional effect on the regeneration of skull base bone tissue.